Porous concrete aggregate



Patented Mar. 10, .UNITED STATES BERNARD J. FALLON,

OF SUMMIT, NEW JERSEY; JOHN F. FALLON, ADMINISTRATOR 0F SAID BERNARD J.FALLON, DECEASED.

'IfQBOUS CONCRETE AGGREGATE.

Io Drawing.

To all whom it may concern:

Be it known that I, Barnum) J. F-ALLoN, a citizen of the UnitedStates,residin at Summit, in the county of Union and tate of New Jersey, haveinvented a certain newnigh degree ofiT'mechanical strength and which, byreason of these characteristics, forms a material particularly adaptedfor use as an aggregate ,in the formation of concrete. It has been foundthat a concrete having as an ingredient a porous solidof the typedescribed, instead of the dense and unporous broken tone usuallemployed, forms an excellent material for use in situations where greatstrength and at the same time light weight is desired, as for instance,in the construction of concrete ships, freight cars, buildings and. thelike.

An important feature of the invention consists incarrying out anessential part of the operation of firing the clayin reducing ordeoxidizing atmosphere, produced by cutting down the supply of air andassing steamthrough the bed of fuel into t e kiln and into contact withthe clay. Another feature of the invention preferably consists inadmitting air or oxygen to the kiln when the deoxidizing action thereonhas reached the desired extent to thereby bring about through thecombustion and expansion of the oxy en in the entering gases with theoxygen eficient gases impermeating the clay a swelling or increase inthe volume of the clay, so as to change it from a'relatively dense andcompact, to a spongy and porous condition.

In carrying out the invention a kiln is g charged with bricks or othersuitable masses of clay and the firing is started and continued in theusual way until a uniform and sufiicient temperature in the entire masshas been reachedand the moisture content has been driven off. I havefound that a temperature of approximately 800.

' Application filed October 80, 1818. Serial No. 334,601.

degrees F. is suflicient for the urpose with many clays. At this stagein are 0 eration the dampers of the kiln are close as far as possibleshort of interrupting the firing operations and all other openings whereair might enter are closed, whereupon steam is let in beneath the bed ofcoals and through which it passes before enterin the kiln andencountering the mass of c ay=under-' goin firing. It will, of course,be recognized that producer as mixed with water gas is thus formed bythe production of carbon dioxide at the first contact of air with thebed of coals and the reduction of the dioxide to carbon monoxide as itpasses through the body of coals, and b the production of carbonmonoxide an free hydrogen from the decomposition of the steam. It willbe seen that the impermeation of the hot mass of cla with theoxygen-deficient carbon monoxi e and hydrogen will gradually produce areducing action on the solid oxygen compounds present in the clay. Thisis particularly manifested in the case of clay containin iron by thereduction of the red and irown ferric compounds to the ferrous compoundswhich are characterized by a blue or black color. When this stage in theoperation is com leted and the temperature of the mass has increased to,for example, 1800 degrees F., I again cause air or oxygen to be admittedto the kiln whereu on the structure of the clay under oes an lmportantchange in its physical and mechanical structure, in that it swells orincreases in volume and becomes porous and spongy to such an extent thatit is extremely llght in weight as compared with the original clay. At'the same time an intense heat is generated by the chemical reactionbetween the oxygen freshly supplied and the 0x gen-deficient gasespresent in the mass at t e end of the reducing action, so that thespongy mass is converted into a vitreous condition.

I believe that the porous effect in the mass is produced by theexpansion of the ases which is probably due in part at least, to theheat of the chemical union, or combination of the oxygen with theoxygendeficient gases such as carbon monoxide and hydrogen that havebeen thoroughly incorporated in the mass of materia during the time,several hours, in extent, that the reducing action has been takingplace. In

setting'- forth this theory I am merely stating what appears, fromobservations made in the course of a long experience in the art of brickmaking, to be what takes place when the oxygen is admitted to the highlyheated mass within the kiln.

In reference to my use of water gas, I am aware that steam hasheretofore been used for various purposes'in firing bricks, but so faras I am informed the introduction of steam to the kilns has invariablybeen accompanied by a sullicient mixture of oxygen to bring aboutperfect combustion, so that no reducing action, such as I havedescribed, can take place. By bringing about the reducing action Isucceed in producing, as has already been indicated, ferrous rather thanferric compounds of the iron constituents present in the particularclays referred to and thus secure a condition of the material that isbest adapted under the further actions described to produce the porouslight-weight and exceedingly strong material that represents the finalproduct. This material is particularly well adapted for use in concretework particularly where lightness as well as strength is sought, as inthe building of ships, freight-cars, buildings and the like, and isobviously equally well adapted for use in any situation where a materialof this general nature may be used.-

What I- claim is:

1. The process of forming a clay product whichconsists in firing a massof cla in a kiln until a uniform temperature has been reached, then inreducing the supply of air and passing steam through the bed of burningfuel into the clay to produce a reducing action thereon, and then insupplying oxygen to the clay to cause the mass to expand and therebyproduce a porous material. 2. The process of forming a clay productwhich consists in firing a mass of clay in a kiln until a temperature ofapproximately 800 F. has been reached, then in reducing the supply ofair and passing steam through the bed of burning fuel into the clay toproduce a reducing action thereon.

3. The process of forming a clay product which consists in firing amassof clay in a kiln until a temperature of approximately 800.? F. hasbeen reached, then in reducing the supply of oxygen and passing steamthrough the bed of burning fuel into the clay to produce a reducinaction on the mass through the action of the oxygen-deficient, gasesissuing from the fuel bed.

4. The process of forming a material for use in construction work whichconsists in firing a mass of argillaceous material to a temperature ofapproximately 800 degrees F., then in reducing the supply of air andpassing steam through the bed of burning fuel and into the materialuntil the tem perature'has reached approximately 1800 degrees F., andthen admitting air to the kiln to cause an expansion of the clay and toconvert the material into a porous vitrified mass.

45. The process of forming a clay product which consists in first firinga mass of clay in a kiln under oxidizing conditions, then in passingsteam through the bed of burning fuel into the presence of the clay andcontinuing the firing of the clay in the atmosphere so produced.

6. The process of forming a material for use in making concrete whichconsists in firing clay in a reducing atmosphere and then in, supplyingoxygen to bring about an expansion of the clay to produce a porousstructure therein.

7. The process of forming a clay product which consists in firing clayin an atmosphere produced by passing steam with an insufficient supplyof air to produce complete combustion through the fuel bed and into thekiln.

8. The process of forming a clay product which consists in first firinga mass of clay in a kiln under oxidizing conditions, then in reducingthe supply of air and passing an oxygen-deficient gas into the presenceof the clay, and in gradually increasing the temperature of the kilnuntil a refractory vitrified condition of the material is produced.

Signed at New York, in the county of New York and State of New York,this 29 day of Oct., 1919.

BERNARD -J. FALLON.

